This invention relates to an electric field machine characterized by a multiplicity of small scale force-generating elements positioned in close proximity to one another to take advantage of the increased force of electric fields with reduced distance of separation.
Conventional electric motors typically include various combinations and arrangements of electrical conductors, magnetic field containment structures, electromagnets, permanent magnets, slip rings, commutators and other mechanical and electromechanical components. These electric motors can be AC powered, DC powered, or powered in a type of stepper operation. For certain uses, conventional electric motors exhibit various desirable characteristics such as efficient operation at design speed, controllability, noncontaminating operation, high output speed, etc. However, there exist a number of problems with conventional electric motors which limit their effectiveness in certain areas of use such as servo control and robot control.
Conventional electric motors develop relatively low field strengths and as a result the output torques are low relative to other types of actuation systems such as hydraulic and pneumatic systems. But, as already mentioned, high output speeds can be achieved and so the combination of low output torques and high speed make electric motors well suited for such things as fans, disc drives, pumps, etc.-- but not for applications where high torque and low output speed are required. Of course, transmission systems can be utilized with the motors to develop a higher torque/lower speed operation, but when a transmission is added, not only is the output torque of the motor increased, a number of undesirable dynamic characteristics of the motor resulting from armature inertia and damping are also increased even more. In other words, the use of transmission systems with electric motors compromises the dynamic performance of the motors. In addition, the use of transmission systems introduces a power loss in motors with a resulting decrease in operating efficiency and increases the weight and cost of the motors.
Another disadvantage of conventional electric motors arises from the use of high mass density magnetic materials and electric conductors which gives a very poor power-to-weight ratio for the motors. This problem is most apparent when conventional electric motors are compared with hydraulic, pnematic, and combustion based power systems.
Finally, the magnitude of magnetic field forces developed in conventional electric motors is dependent upon the current carrying capabilities of the conductors which, in turn, is dependent upon the size (cross-section) of the conductors. Any attempt at reducing the scale of such magnetic-field based motors would result in a significant reduction of the forces and thus a diminishment of the utility of the motors.